Compact, physics-based modeling of nanoscale limits of double-gate MOSFETs

Compact, physics-based models of subthreshold swing and threshold voltage are presented for double-gate (DG) MOSFETs in symmetric, asymmetric, and ground-plane modes. Applying these device models, threshold voltage variations in DG MOSFETs are comprehensively and exhaustively investigated using a unique, scale-length based methodology. Quantum mechanical effects and fringe-induced barrier lowering effect on threshold voltage, caused by ultra-thin silicon film and potential use of high-permittivity gate dielectrics, respectively, have been analytically modeled giving close agreement to numerical simulations. Scaling limits projections indicate that individual DG MOSFETs with good turn-off behavior are feasible at 10 nm scale; however, practical exploitation of these devices toward gigascale integrated systems requires development of novel technologies for significant improvement in process control.